Multi-panel overhead garage doors are used to provide a convenient and compact means for access to garages. However, it is difficult for an individual to lift the door because of its weight. In addition, after the door has been lifted, it is necessary to prevent the door from returning to a closed position until so desired by the individual.
To solve these problems, springs have been used. These springs are either directly connected to a bottom bracket which is in turn secured to the bottom panel of the garage door as shown in Dautrick U.S. Pat. No. 2,495,672, or they are connected to the bottom bracket through a cable or other flexible means as shown in Johnson U.S. Pat. No. 2,008,959. In either case, when the door is down or closed, the spring is at its maximum stretch or torsion and is under relatively high tension. This tension provides enough lift to allow an ordinary person to easily lift or open the garage door. As the door is lifted, the panels move into a horizontal position along a track thereby reducing the portion of the door tending to resist the lift. At the same time, the spring stretch is being reduced. Nevertheless, when the door is in the up or open position, the tension in the spring is sufficient to prevent the garage door from closing without initiation by a person.
In all of the prior art systems, the bottom bracket is secured to the garage door end stile or bottom panel solely by screws (Kaiser U.S. Pat. No. 2,436,006), bolts (Moler U.S. Pat. No. 3,412,780), or other removable devices. Although these devices serve to adequately secure the bottom bracket to the door, a problem arises if they are loosened or removed.
If the fastening devices are removed, the bottom bracket becomes disengaged from the garage door. This can be safely done if the spring or cable has first been disengaged. If, however, the fastening devices are removed (or disengage on their own) while the spring is attached and under high tension (as when the door is in the closed position), a potentially catastrophic event can occur. The bottom bracket then becomes a projectile acting under the full force of the spring. Any nearby person could be seriously injured if such an event occurred.
Therefore, there is a significant need for a means of preventing the bottom bracket from separating from the garage door when the bottom bracket is attached to the springs under tension and the fastening devices are removed. Further, these means should not hinder in the attachment and removal of the bracket from the garage door when the bracket is not secured to the spring.